A toothed belt is usually trained between a driving toothed pulley and a driven toothed pulley and has been used as a power transmitting belt for general industrial equipment or OA (Office Automation) equipment, a timing belt for an automobile internal-combustion engine, a driving belt for a bicycle, and the like. The toothed belt is usually comprised of a carbon black-containing black belt body rubber layer in which a plurality of core strands is buried in the longitudinal direction of the belt. On a surface of this belt body, a rubber layer forms a plurality of teeth portions and on the surface of the teeth portions is a tooth cloth formed in a coated manner.
A toothed belt has been previously described in which a first rubber composition consisting of polytertafluoroethylene (PTFE) and carbon black-containing hydrogenated nitrile rubber (HNBR) is dissolved in a solvent. The dissolved subject is then immediately impregnated into an original canvas to form a teeth canvas layer and an adhesive rubber is applied to a back side of the teeth canvas layer so that the obtained structure is adhered to a belt body rubber layer (Japanese Laid-open Patent Publication No. Hei. 7-151190).